FAILED: patch "[PATCH] ALSA: hda/hdmi: clamp sad_count in ELD proc write handler" failed to apply to 6.12-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x b3e7ddd694f8429217ba509b55b910a0e4361dfb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107052016-failed-6.12-b3e7ddd694f8@kernel.org' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From b3e7ddd694f8429217ba509b55b910a0e4361dfb Mon Sep 17 00:00:00 2001
From: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Date: Thu, 8 Oct 2026 11:51:33 +0300
Subject: [PATCH] ALSA: hda/hdmi: clamp sad_count in ELD proc write handler

snd_hdmi_write_eld_info() parses a "sad_count N" line from the
root-writable ELD proc interface and assigns N directly to
e->sad_count with no upper bound, unlike the per-index "sadN_*" lines
a few lines below which are already bounded to ELD_MAX_SAD.

snd_hdmi_eld_update_pcm_info() later iterates
"for (i = 0; i < e->sad_count; i++)" over the fixed
e->sad[ELD_MAX_SAD] array, so an oversized sad_count read from the
proc file causes it to walk past the array.

Reject sad_count values above ELD_MAX_SAD, matching the existing
per-index guard.

Fixes: acb059938810 ("ALSA: hda - ELD proc interface write updates")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://patch.msgid.link/20261008085133.9528-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/hda/codecs/hdmi/eld.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sound/hda/codecs/hdmi/eld.c b/sound/hda/codecs/hdmi/eld.c
index 1464fd1c675bc..fc6fe1b0873c3 100644
--- a/sound/hda/codecs/hdmi/eld.c
+++ b/sound/hda/codecs/hdmi/eld.c
@@ -155,9 +155,11 @@ void snd_hdmi_write_eld_info(struct hdmi_eld *eld,
 			e->aud_synch_delay = val;
 		else if (!strcmp(name, "speakers"))
 			e->spk_alloc = val;
-		else if (!strcmp(name, "sad_count"))
+		else if (!strcmp(name, "sad_count")) {
+			if (val > ELD_MAX_SAD)
+				continue;
 			e->sad_count = val;
-		else if (!strncmp(name, "sad", 3)) {
+		} else if (!strncmp(name, "sad", 3)) {
 			sname = name + 4;
 			n = name[3] - '0';
 			if (name[4] >= '0' && name[4] <= '9') {
-- 
2.53.0